Adjustable current shield for electroplating processes

ABSTRACT

One illustrative plating apparatus disclosed herein includes a substrate holder that is adapted to receive a substrate, an anode and an adjustable current shield positioned between the substrate holder and the anode. In this illustrative embodiment, the adjustable current shield includes a stationary member, a moveable member that is adapted to be moved relative to the stationary member and a plurality of current shield members that are operatively coupled to either the stationary member or the moveable member, wherein each of the current shield members is rotatably pinned to either the stationary member or the moveable member and wherein each of the current shield members is adapted to rotate when there is relative movement between the moveable member and the stationary member.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Generally, the present disclosure relates to the manufacture of sophisticated semiconductor devices, and, more specifically, to an adjustable current shield that may be employed in electroplating processes that are performed to form a conductive metal material.

2. Description of the Related Art

The manufacture of semiconductor devices often requires the formation of electrical conductors on semiconductor wafers. For example, electrically conductive leads on the wafer are often formed by electroplating (depositing) an electrically conductive layer, such as copper, on the wafer and into patterned trenches. There are two general types of electroplating equipment: fountain plating equipment and vertical plating equipment. Both have relative advantages in some applications. Although the orientation of the surface of the wafer to be plated is different in the two different processes—horizontal in fountain plating equipment and vertical in vertical plating equipment—the process operations are very similar.

In general, electroplating involves making electrical contact with a so-called conductive “seed” layer that is formed on the wafer surface upon which the electrically conductive layer, e.g., copper, is to be deposited. Current is then passed through a plating solution (i.e., a solution containing ions of the element being deposited, for example, a solution containing Cu⁺⁺) between an anode and the conductive seed layer on the wafer plating surface that acts as a cathode. The seed layer carries the electrical plating current from the edge of the wafer, where electrical contact is made, to the center of the wafer, including through embedded structures, trenches and vias. This causes an electrochemical reaction on the wafer plating surface which results in the deposition of the electrically conductive layer. Ideally, the final layer of material that is electrodeposited on the seed layer should completely fill the embedded structures, and it should have a specific thickness profile across the surface of the wafer. Generally, in electroplating processes, the thickness profile of the deposited metal should be controlled as much as possible.

In an attempt to minimize variations in the deposited material, it is important that the electrically conductive seed layer have a uniform thickness over the wafer plating surface. However, even with highly uniform seed layers, conventional electroplating processes produce a non-uniform deposition due to the so-called “edge effect” associated with such plating processes. In general, the edge effect refers to the tendency of the deposited electrically conductive layer to be thicker near the wafer edge than at the wafer center, i.e., an “edge-thick” profile. This edge-thick profile in the final layer is caused by, among other things, a decrease in current flow through the seed layer in the middle region of the wafer as compared to the current flowing near the edge region of the wafer. That is, since the conductive seed layer is contacted at the periphery of the wafer and the magnitude of the current flowing through the seed layer drops as one moves from the edge of the wafer toward the center of the wafer, there is less conductive material, e.g., copper, plated at the center of the wafer as compared to the edge region of the wafer.

The formation of such edge-thick layers of material makes subsequent processing more difficult. For example, such edge-thick layers of material make subsequent chemical mechanical polishing operations more difficult to perform, i.e., it makes it more difficult to obtain a substantially planar surface after the polishing process has been performed. As another example, various processing parameters of the electroplating process may be adjusted in an attempt to combat this tendency to produce conductive material layers with an edge-thick profile. However, such processing changes may result in producing a conductive layer that is too thin in the middle area of the wafer, thereby leading to the formation of defective wiring features that are not as thick as intended by the design process. Such defective wiring features may reduce the useful life of an integrated circuit product and, in a worst-case scenario, may lead to complete device failure.

One technique that has been employed in an effort to avoid or reduce the magnitude of the production of such edge-thick conductive layers involves the use of so-called current shields. Current shields are typically positioned between the anode and the wafer and they act to reduce the electrical field at the edge region of the wafer, which reduces the amount of the conductive material formed on the edge region of the wafer. The current shields may be made of a variety of materials, such as non-conductive, inert materials, like plastic. The current shields may be fixed or adjustable in terms of their area that is positioned between the anode and the wafer. In one example, a fixed current shield has a radial width of about 20-30 mm and a thickness on the order of about 2-3 mm. Such fixed current shields are typically sized and configured for a particular process flow and/or device by a trial and error process. Once acceptable results are achieved, the specifically designed current shield is used in production operations. Unfortunately, when there is a change in the design of the wafer or the process conditions, the existing current shield may not produce acceptable results. In that case, a new design of a current shield may need to be determined (by trial and error) and then put into production service. Alternatively, processing engineers may try to “make-do” with the less than desirable original current shield, which may lead to the production of conductive layers that do not have the desired or target thickness profile and the problems associated with such layers as discussed above.

The present disclosure is directed to a novel adjustable current shield that may solve or reduce one or more of the problems identified above.

SUMMARY OF THE INVENTION

The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an exhaustive overview of the invention. It is not intended to identify key or critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is discussed later.

Generally, the present disclosure is directed to a plating tool that includes an adjustable current shield that may be employed in electroplating process operations. One illustrative plating apparatus disclosed herein includes a substrate holder that is adapted to receive a substrate, an anode and an adjustable current shield positioned between the substrate holder and the anode. In this illustrative embodiment, the adjustable current shield includes a stationary member, a moveable member that is adapted to be moved relative to the stationary member and a plurality of current shield members that are operatively coupled to either the stationary member or the moveable member, wherein each of the current shield members is rotatably pinned to either the stationary member or the moveable member and wherein each of the current shield members is adapted to rotate when there is relative movement between the moveable member and the stationary member.

Another illustrative plating apparatus disclosed herein includes a substrate holder that is adapted to receive a substrate, an anode and an adjustable current shield positioned between the substrate holder and the anode. In this illustrative embodiment, the adjustable current shield includes a stationary ring, a moveable ring that is adapted to be moved relative to the stationary ring and a plurality of current shield members operatively coupled to the stationary ring and the moveable ring, wherein each of the plurality of current shield members is rotatably pinned to either the stationary ring or the moveable ring and wherein each of the current shield members is adapted to rotate when there is relative movement between the moveable ring and the stationary ring, thereby moving a portion of each of the current shield members radially inward or outward depending upon the direction of the relative movement.

Yet another illustrative plating apparatus disclosed herein includes a substrate holder that is adapted to receive a substrate, an anode and an adjustable current shield positioned between the substrate holder and the anode, wherein the adjustable current shield includes a plurality of segmented shielding members that may be moved so as to effectively change a size of an opening of the adjustable current shield.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure may be understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements, and in which:

FIGS. 1 and 1A are simplistic and schematic views of various illustrative embodiments of an electroplating apparatus having an adjustable current shield as disclosed herein;

FIGS. 2A-2E depict various illustrative aspects of one illustrative embodiment of an adjustable current shield as disclosed herein; and

FIGS. 3A-3B depict one illustrative embodiment of a plurality of current shielding members that may be employed in the illustrative adjustable current shield disclosed herein.

While the subject matter disclosed herein is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION

Various illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.

The present subject matter will now be described with reference to the attached figures. Various structures, systems and devices are schematically depicted in the drawings for purposes of explanation only and so as to not obscure the present disclosure with details that are well known to those skilled in the art. Nevertheless, the attached drawings are included to describe and explain illustrative examples of the present disclosure. The words and phrases used herein should be understood and interpreted to have a meaning consistent with the understanding of those words and phrases by those skilled in the relevant art. No special definition of a term or phrase, i.e., a definition that is different from the ordinary and customary meaning as understood by those skilled in the art, is intended to be implied by consistent usage of the term or phrase herein. To the extent that a term or phrase is intended to have a special meaning, i.e., a meaning other than that understood by skilled artisans, such a special definition will be expressly set forth in the specification in a definitional manner that directly and unequivocally provides the special definition for the term or phrase.

The present disclosure is directed to an electroplating tool that includes an adjustable current shield that may be employed in electroplating process operations. As will be readily apparent to those skilled in the art upon a complete reading of the present application, the methods and devices disclosed herein may be employed in a variety of different manufacturing applications and techniques, e.g., standard plating operations to form a uniform conductive layer, patterned plating applications, etc. Moreover, the methods and devices disclosed herein may also be employed in manufacturing a variety of different devices, including, but not limited to, logic devices, memory devices, etc. With reference to the attached figures, various illustrative embodiments of the methods and devices disclosed herein will now be described in more detail.

FIG. 1 depicts, in schematic and simplistic form, a fountain-type electroplating apparatus 10 in accordance with one illustrative embodiment disclosed herein, wherein the adjustable current shield 100 disclosed herein is oriented substantially horizontal within the apparatus 10 and located vertically above the anode. However, as will be recognized by those skilled in the art, the adjustable current shield disclosed herein may also be employed in vertical-type plating tools, wherein the adjustable current shield 100 disclosed herein is oriented substantially vertical in such a vertical plating tool, as schematically depicted in FIG. 1A. The disclosed electroplating apparatus 10 contains a main plating bath container 12 that contains a conventional electroplating bath 14 comprised of an electrolytic plating fluid. A cylindrical container wall 16 determines the height 18 of the plating bath 14. The electroplating apparatus 10 further includes a substrate/wafer holder 20 and a schematically depicted anode 30. The substrate holder 20 is adapted to hold an integrated circuit substrate 22. A motor (not shown) drives a spindle 26 that rotates the substrate holder 20 and substrate 22 around a central axis during plating operations. The substrate 22 has a substrate backside 22B and a substrate front plating surface 22F. The front plating surface 22F typically has a conductive seed layer (not shown) formed thereon to facilitate plating operations, e.g., a conductive copper seed layer or a tantalum or titanium nitride barrier layer. The shape and configuration of the substrate holder 20 may vary depending upon the type of plating apparatus employed. In some cases, the substrate holder 20 may include a compliant O-ring seal (not shown) and a set of electrical contacts (not shown) for electrically connecting the negative terminal of a power source 24 to the conductive seed layer (not shown) at the edge of the substrate 20. The positive terminal of the power source 24 is conductively coupled to the anode 30. The substrate 22 may be comprised of any semiconducting material, such as silicon, silicon/germanium, ruby, quartz, sapphire and gallium arsenide. The anode 30 is illustrative in nature in that it may be comprised of multiple parts arranged in a variety of configurations and it may have multiple openings.

Also shown in FIG. 1, the electroplating apparatus also includes a schematically depicted adjustable current shield 100 as disclosed herein. In general, the adjustable current shield 100 is disposed between the anode 30 and the substrate 22 or substrate holder 20. The adjustable current shield 100 may be secured to the container wall 16 by any desired technique, e.g., clips, lugs, bolted connections, etc. The periphery of the adjustable current shield 100 need not be sealed against the inner surface of the container wall 16. The adjustable current shield 100 may be positioned at any desired distance from the substrate 22, and this distance may vary depending upon the particular application. For example, the position of the adjustable current shield 100 may be determined, at least in part, based upon the desired thickness profile of the electrically conductive layer to be deposited on the substrate 22. In general, the closer the adjustable current shield 100 is positioned to the substrate 22, the greater the influence the adjustable current shield 100 has on the resulting thickness profile of the electrically conductive layer to be deposited on the wafer 22. The adjustable current shield 100 as well as the container wall 16 may be comprised of materials that resist attack by the electrolytic plating fluid in the bath 14. These structures may be comprised of a dielectric material or a composite material that includes a dielectric coating to prevent electroplating of metal onto these structures during the electroplating process. These structures may also be made of various plastics, such as polypropylene, polyethylene and fluoro-polymers, especially polyvinylidine fluoride, or ceramics such as alumina or zirconia. The apparatus 10 depicted in FIG. 1 is a simplistic and schematic depiction of an illustrative fountain-type plating tool, the basic construction of which is well known to those skilled in the art. As noted earlier, the adjustable current shield 100 disclosed herein may be employed in so-called vertical plating tools as well, the basic construction of which is also well known to those skilled in the art. FIG. 1A is a simplistic and schematic depiction of some of the major components of such a vertical plating apparatus. More specifically, as shown in FIG. 1A, in some embodiments, the substrate holder 20, substrate 22, adjustable current shield 100 and the anode 30 may all be oriented substantially vertically, wherein the adjustable current shield 100 is located laterally between the substrate holder 20 and the anode 30.

The illustrative electroplating bath 14 is a conventional bath that typically contains the metal to be plated, together with associated anions, in an acidic solution. Copper electroplating is usually performed using a solution of CuSO₄ dissolved in an aqueous solution of sulfuric acid. In addition to these major constituents of the electroplating bath 14, it is common for the bath 14 to contain several additives, which are any type of compound added to the plating bath 14 to change the plating behavior. Three types of electroplating bath additives are in common use, subject to design choice by those skilled in the art: suppressors, accelerators and levelers. Suppressor additives retard the plating reaction and increase the polarization of the cell. Accelerator additives are normally catalysts that accelerate the plating reaction under suppression influence or control. Levelers behave like suppressors, but are highly electrochemically active (i.e., are more easily electrochemically transformed), losing their suppressive character upon electrochemical reaction. Levelers also tend to accelerate plating on depressed regions of the surface undergoing plating, thus, tending to level the plated surface. Of course, as will be appreciated by those skilled in the art after a complete reading of the present application, the inventions disclosed herein are not limited to use with any type of plating bath, as the inventions disclosed herein may be employed with a variety of different bath chemistries.

General aspects of a typical plating process will now be described. As will be appreciated by those skilled in the art, the container wall 16 of the plating apparatus 10 functions as an overflow weir. During typical operations, the substrate holder 20 is partially submerged in the plating bath 14 such that the electrolytic plating fluid wets plating surface 22F of the substrate 22 but does not wet the upper portions of substrate holder 20. In general, the plating fluid overflows the container/weir 16, as indicated by the arrows 32, into the space between the main plating bath container 12 and container wall 16. Thereafter, as indicated by the arrows 34, the plating fluid flows to the inlet 36 of a circulating pump 38. During operations, the circulating pump 38 typically continuously circulates plating fluid to the plating bath 14, as indicated by the arrow 26. In this manner, the bath height 18 may be maintained during plating operations. Generally, the plating solution flows upwards through openings (not shown) in the anode 30 and around the anode 30 toward the substrate 22. During use, the power supply 24 biases the wafer 22 to have a negative potential relative to the anode 30, causing an electrical current to flow from the anode 30 to the substrate 22. This also causes an electric current flux from the anode 30 to the substrate 22, wherein the electric current flux is defined as the number of lines of forces (field lines) through an area. This causes an electrochemical reaction (e.g., Cu⁺⁺+2e⁻=Cu) which results in the deposition of the electrically conductive layer (e.g., copper) on the on the front face 22F of the substrate 22. The ion concentration of the desired metal in the plating solution may be replenished during the plating cycle by dissolving a metal of the anode 30, e.g., copper, in the plating solution.

FIGS. 2A-2E depict various aspects of the illustrative example of an adjustable current shield 100 as disclosed herein. FIGS. 3A-3B depict one illustrative example of a plurality of current shielding members that may be employed in the illustrative adjustable current shield 100 disclosed herein. In general, in the disclosed example, the adjustable current shield 100 is comprised of a stationary ring 102 (see FIGS. 2A-2B), an adjustable or moveable ring 112 (see FIGS. 2C-2D) and a plurality of current shielding members 130 (see FIGS. 3A-3B). In operation, as described more fully below, the moveable ring 112 is adapted to be moved relative to the stationary ring 102. This relative movement of the moveable ring 112 causes a portion (136) of each of the current shielding members 130 to move radially inward, thereby effectively changing the “size” of the shielding members 130 and their shielding capability.

FIGS. 2A-2B, depict various aspects of one illustrative example of the stationary ring 102. In the depicted example, the stationary ring 102 has an inner surface 104, an outer surface 106 and a ledge 110 that defines a recess 111 that is adapted to receive the moveable ring 112. A plurality of pins 108 are attached to the stationary ring 102. The stationary ring 102 may be secured to the container wall 16 of the plating apparatus 10 by any desired technique, e.g., clips, lugs, bolted connections, etc. (not shown). The outer surface 106 of the stationary ring 102 need not be sealed against the inner surface of the container wall 16. The physical size of the stationary ring 102 may vary depending upon a variety of factors, including the size of the plating apparatus 10 in which it will be employed and the mechanical loading it is anticipated to experience in operation. In one illustrative example, the stationary ring 102 may have a radial thickness (outside diameter minus inside diameter) of about 5-50 mm, and an overall thickness of about 5-25 mm. The stationary ring 102 may be made of a dielectric material or a composite material that includes a dielectric coating various plastics, such as polypropylene, polyethylene, and fluoro-polymers, especially polyvinylidine fluoride, or ceramics such as alumina or zirconia. The number, size and location of the pivot pins 108 may also vary depending upon the particular application and the number of current shielding members 130 employed in the adjustable current shield 100.

FIGS. 2C-2D depict various aspects of one illustrative example of a moveable ring 112 that may be employed in the adjustable current shield 100 disclosed herein. In the depicted example, the moveable ring 112 has an inner surface 114 and an outer surface 116. A plurality of pins 118 are attached to the stationary ring 102. As shown in FIG. 2E, the moveable ring 112 is adapted to be positioned in the recess 111 formed in the stationary ring 102. Any of a variety of means may be provided for causing movement of the moveable ring 112 relative to the stationary ring 102. In the depicted example, such means may include a plurality of schematically depicted gear teeth 113 that are coupled to the moveable ring 112. The gear teeth 113 are adapted to be engaged by a driving member or device (not shown in FIG. 2C) to cause relative movement of the moveable ring 112. Alternatively, such means may include a schematically depicted lever 115 that is coupled to the moveable ring 112. The lever 115 is adapted to be engaged by a driving member or device (not shown in FIG. 2C) or manually to cause relative movement of the moveable ring 112. The physical size of the moveable ring 112 may vary depending upon a variety of factors, including the size of the plating apparatus 10 in which it will be employed and the mechanical loading it is anticipated to experience in operation. In one illustrative example, the moveable ring 112 may have a radial thickness (outside diameter minus inside diameter) of about 5-30 mm, and an overall thickness of about 5-20 mm. The moveable ring 112 may be made of a dielectric material or a composite material that includes a dielectric coating various plastics, such as polypropylene, polyethylene, and fluoro-polymers, especially polyvinylidine fluoride, or ceramics such as alumina or zirconia. The number, size and location of the pins 118 may also vary depending upon the particular application and the number of current shielding members 130 employed in the adjustable current shield 100.

FIGS. 3A-3B depict one illustrative example of a plurality of current shielding members 130 that may be employed with the adjustable current shield 100 disclosed herein. FIG. 3B is somewhat of an assembly drawing of the adjustable current shield 100 with the stationary ring 102 and the moveable ring 112 depicted in dashed lines. As will be appreciated by those skilled in the art after a complete reading of the present application, the size, number, shape and configuration of the current shielding members 130 employed with the adjustable current shield 100 disclosed herein may vary depending on the particular application. In the example depicted in FIG. 3A, each of the current shielding members 130 has a generally elongated, curved configuration. In the embodiment disclosed herein, each of the current shielding members 130 comprises a pivot hole 132 and a slot 134. In this example, the pivot hole 132 is adapted to receive and operatively cooperate with one of the pins 108 on the stationary ring 102, while the slot 134 is adapted to receive and operatively cooperate with one of the pins 118 on the moveable ring 112. If desired, the positions of the hole 132 and the slot 134 on the current shielding member 130 may be interchanged, but the orientation of the slot 134 would need to be rotated ninety degrees as compared to the orientation of the slot 134 that is depicted in the drawings. In some embodiments, the slots 134 may have some degree of curvature, although that is not depicted in the attached drawings. The number and physical size of the current shielding members 130 may vary depending upon a variety of factors, including the size of the plating apparatus 10 in which they will be employed and the mechanical loading the current shielding members 130 are anticipated to experience in operation. In one illustrative example, the current shielding members 130 may have a width 130W of about 10-30 mm, and an overall thickness of about 1-3 mm. The current shielding members 130 may be made of a dielectric material or a composite material that includes a dielectric coating various plastics, such as polypropylene, polyethylene, and fluoro-polymers, especially polyvinylidine fluoride, or ceramics such as alumina or zirconia.

With reference to FIG. 3B, in one embodiment, the gear teeth 113 on the moveable ring 112 are adapted to be engaged by teeth 142 on an illustrative drive motor 140, such as a stepper motor. In one embodiment, the drive motor 140 is adapted to cause rotation of the moveable ring 112 in either of the directions indicated by the arrows 150 (clockwise) or 152 (counterclockwise). Accordingly, in this embodiment, the drive motor 140 constitutes part of the means for causing relative movement of the moveable ring 112. The illustrative lever 115 may also be moved in the directions 160, 162 to cause relative movement of the moveable ring 112. Movement of the lever 115 may be accomplished manually or by electromechanical means, such as by an electric motor (not shown) coupled to the lever 115 by appropriate mechanical linkage.

In the example depicted in FIG. 3B, eight of the illustrative current shielding members 130 are employed as part of the illustrative adjustable current shield 100 disclosed herein. Of course, as noted above, the number of such current shielding members 130 employed in any particular plating apparatus 10 may vary depending upon the particular application. The adjustable current shield 100 is depicted in its fully closed position in FIG. 3B, wherein the current shielding members 130 have their smallest effective width as it relates to acting as a current shield during plating operations. In the particular example depicted herein, a distal portion 136 (see FIG. 3A) of each of the current shielding members 130 is positioned above a portion of an adjacent current shielding member 130, and in some cases may contact the adjacent current shielding member 130. The amount or degree to which the distal portion 136 overlaps an adjacent current shielding member 130 may vary depending upon the particular application. In some embodiments, there may be no such overlap at all.

The effective width of the current shielding members 130 may be adjusted as follows. Rotation of the moveable ring 112 relative to the stationary ring 102 (by means of the lever 115 or the motor 140/gear teeth 113/142) in the direction indicated by the arrow 150 causes a portion of the current shielding members 130 to be extended radially inward, in the direction indicated by the arrow 150A, to thereby increase the effective width of the adjustable current shield 100. During this process, the current shielding members 130 pivot around the pin 108 on the stationary ring 102. The slot 134 cooperates with the pin 118 on the moveable ring 112 to allow the movement of the current shielding member 130. The amount or extent to which the current shielding members 130 may move radially inward depends upon the desired effective width of the adjustable current shield 100 and the specific design of the plating apparatus. Normally, the adjustable current shield 100 will have a limit on how far the moveable ring 112 may be rotated relative to the stationary ring 102, which will correspond to a maximum displacement of the current shielding members 130 (not shown) in the radially inward direction 150A. In some cases, to the extent that each of the current shielding members 130 overlapped with an adjacent current shielding member 130 when the adjustable current shield 100 was in its fully closed position (as shown in FIG. 3B), such an overlapping relationship may not exist when the current shielding members 130 are shifted inward. Rotation of the moveable ring 112 relative to the stationary ring 102 (by means of the lever 115 or the motor 140/gear teeth 113/142) in the direction indicated by the arrow 152 (counterclockwise) causes the current shielding members 130 to be moved in a radially outward direction, as indicated by the arrow 152A, to thereby decrease the effective width of the adjustable current shield 100. Once the adjustable current shield 100 is adjusted such that the current shielding members 130 are positioned so as to provide the desired amount of current shielding during plating operations, the adjustable current shield 100 may be locked or secured in this desired position by any suitable means.

As will be appreciated by those skilled in the art after a complete reading of the present application, the adjustable current shield 100 provides several advantages as it relates to performing plating operations. For example, to the extent that there is a change in the design of the substrates to be processed through the plating apparatus 10, or a change in the processing parameters, the adjustable current shield 100 provides a readily adjustable means by which a process engineer may attempt to reduce or eliminate the problems associated with producing plated metal layers with an edge-thick profile. Moreover, by adjusting the shape, size and/or number of current shielding members 130, as well as the extent to which portions of the current shielding members 130 may be positioned radially inward, a process engineer has greater processing flexibility to “tune” plating operations as necessary. In one embodiment, the subject matter disclosed herein is directed to a plating apparatus that includes a plurality of segmented shielding members that may be actuated simultaneously or individually to effectively change the size (effective diameter) of the opening or aperture of a substantially circular current shield.

The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. For example, the process steps set forth above may be performed in a different order. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below. 

What is claimed:
 1. A plating apparatus, comprising: a substrate holder that is adapted to receive a substrate; an anode; and an adjustable current shield positioned between said substrate holder and said anode, wherein said adjustable current shield comprises: a stationary member; a moveable member that is adapted to be moved relative to said stationary member; and a plurality of current shield members operatively coupled to said stationary member and said moveable member, wherein each of said plurality of current shield members is rotatably pinned to one of said stationary member or said moveable member and wherein each of said current shield members is adapted to rotate when there is relative movement between said moveable member and said stationary member.
 2. The apparatus of claim 1, wherein said substrate holder is located vertically above said anode and said adjustable current shield is located vertically above said anode.
 3. The apparatus of claim 1, wherein each of said substrate holder, said anode and said adjustable current shield are oriented substantially vertically, and wherein said adjustable current shield is located laterally between said substrate holder and said anode.
 4. The apparatus of claim 1, wherein said stationary and moveable members each have a ring configuration.
 5. The apparatus of claim 1, further comprising means for moving said moveable member relative to said stationary member.
 6. The apparatus of claim 1, further comprising a plurality of gear teeth that are operatively coupled to said moveable member.
 7. The apparatus of claim 1, further comprising a lever that is operatively coupled to said moveable member.
 8. The apparatus of claim 1, wherein, when said adjustable current shield is in a fully closed position, a portion of each of said plurality of current shielding members overlaps a portion of an adjacent current shielding member.
 9. The apparatus of claim 1, wherein, when said adjustable current shield is in a fully closed position, a portion of each of said plurality of current shielding members overlaps and contacts a portion of an adjacent current shielding member.
 10. A plating apparatus, comprising: a substrate holder that is adapted to receive a substrate; an anode; and an adjustable current shield positioned between said substrate holder and said anode, wherein said adjustable current shield comprises: a stationary member; a moveable member that is adapted to be moved relative to said stationary member; and a plurality of current shield members operatively coupled to said stationary member and said moveable member, wherein each of said plurality of current shield members is rotatably pinned to one of said stationary member or said moveable member and wherein a portion of each of said current shield members is adapted to be moved inward or outward when there is relative movement between said moveable member and said stationary member depending upon the direction of such relative movement.
 11. The apparatus of claim 10, wherein, when said adjustable current shield is in a fully closed position, a portion of each of said plurality of current shielding members overlaps a portion of an adjacent current shielding member.
 12. The apparatus of claim 11, wherein, when said adjustable current shield is in a fully closed position, a portion of each of said plurality of current shielding members overlaps and contacts a portion of an adjacent current shielding member.
 13. The apparatus of claim 10, wherein said substrate holder is located vertically above said anode and said adjustable current shield is located vertically above said anode.
 14. The apparatus of claim 10, wherein each of said substrate holder, said anode and said adjustable current shield are oriented substantially vertically, and wherein said adjustable current shield is located laterally between said substrate holder and said anode.
 15. A plating apparatus, comprising: a substrate holder that is adapted to receive a substrate; an anode; and an adjustable current shield positioned between said substrate holder and said anode, wherein said adjustable current shield comprises: a stationary ring; a moveable ring that is adapted to be moved relative to said stationary ring; and a plurality of current shield members operatively coupled to said stationary ring and said moveable ring, wherein each of said plurality of current shield members is rotatably pinned to one of said stationary ring or said moveable ring and wherein each of said current shield members is adapted to rotate when there is relative movement between said moveable ring and said stationary ring, thereby moving a portion of each of said current shield members radially inward or outward depending upon the direction of such relative movement.
 16. The apparatus of claim 15, wherein said substrate holder is positioned above said anode and said adjustable current shield is positioned above said anode.
 17. The apparatus of claim 15, further comprising means for moving said moveable member relative to said stationary member.
 18. The apparatus of claim 15, wherein, when said adjustable current shield is in a fully closed position, a portion of each of said plurality of current shielding members overlaps a portion of an adjacent current shielding member.
 19. The apparatus of claim 15, wherein, when said adjustable current shield is in a fully closed position, a portion of each of said plurality of current shielding members overlaps and contacts a portion of an adjacent current shielding member.
 20. The apparatus of claim 15, wherein said substrate holder is located vertically above said anode and said adjustable current shield is located vertically above said anode.
 21. The apparatus of claim 15, wherein each of said substrate holder, said anode and said adjustable current shield are oriented substantially vertically, and wherein said adjustable current shield is located laterally between said substrate holder and said anode.
 22. A plating apparatus, comprising: a substrate holder that is adapted to receive a substrate; an anode; and an adjustable current shield positioned between said substrate holder and said anode, wherein said adjustable current shield comprises: a stationary ring; a moveable ring that is adapted to be moved relative to said stationary ring; and a plurality of current shield members operatively coupled to said stationary ring and said moveable ring, wherein each of said plurality of current shield members is rotatably pinned to said stationary ring and wherein each of said current shield members is adapted to rotate when said moveable ring is moved relative to said stationary ring, thereby moving a portion of each of said current shield members radially inward or outward depending upon the direction of movement of said moveable ring relative to said stationary ring.
 23. The apparatus of claim 22, wherein, when said adjustable current shield is in a fully closed position, a portion of each of said plurality of current shielding members overlaps a portion of an adjacent current shielding member.
 24. The apparatus of claim 23, wherein, when said adjustable current shield is in a fully closed position, a portion of each of said plurality of current shielding members overlaps and contacts a portion of an adjacent current shielding member.
 25. The apparatus of claim 22, wherein said substrate holder is located vertically above said anode and said adjustable current shield is located vertically above said anode.
 26. The apparatus of claim 22, wherein each of said substrate holder, said anode and said adjustable current shield are oriented substantially vertically, and wherein said adjustable current shield is located laterally between said substrate holder and said anode.
 27. A plating apparatus, comprising: a substrate holder that is adapted to receive a substrate; an anode; and an adjustable current shield positioned between said substrate holder and said anode, wherein said adjustable current shield comprises a plurality of segmented shielding members that may be moved so as to effectively change a size of an opening of said adjustable current shield.
 28. The apparatus of claim 27, wherein, when said adjustable current shield is in a fully closed position, a portion of each of said plurality of segmented shielding members overlaps and contacts a portion of an adjacent segmented shielding member.
 29. The apparatus of claim 27, wherein a portion of each of said plurality of segmented shielding members is adapted to move radially inward or outward when moved.
 30. The apparatus of claim 27, wherein said size is an effective diameter of said opening. 